Well tool string



July 8, 1969` C. C, BROWN 3,454,090

WELL 'rooL STRING original Filed July 12, 1967 Sheet of 5 v'f .d

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v I" S v a f4.' @ma-560W I BY` ATTORNEY C. C. BROWN WELL TOOL STRINGJuly 8, 1969 Sheet f8 of 5 Original Filed-July 12, 1967 C. c. BROWN yWELL TOOL STRING July 8, 1969 sheet 3 of 5 Original Filed July 12. 1967C. C. BROWN July 8, 1969 v WELL TOOL STRING Original Filed July 12,196'/ Shoot of 5 July s, 1969 C. C, BROWN 3,454,090

WELL TOOL STRING d 1 12, 19e Original File Ju y '7 sheet 5 of 5 s GWWN 765H0 C. WN c/INVEN R.

United States Patent O 3,454,090 WELL TOOL STRING Cicero C. Brown, BrownOil Tools, Inc.,

P.O. Box 19236, Houston, Tex. 77024 Original application July 12, 1967,Ser. No. 652,817, now Patent No. 3,409,096, dated Nov. 5, 1968. Dividedand this application June 12, 1968, Ser. No. 736,531

Int. Cl. E21b 23/00, 33/12, 33/13 U.S. Cl. 166-138 6 Claims ABSTRACT FTHE DISCLOSURE A tool string for enabling a plurality of operations tobe performed in a well bore with one primary pipe string withoutremoving the latter from the well bore. The operations include drilling,cementing, packing-off, perforating, squeezing and the like.

Related applications This application is a division of my copendingapplication Ser. No. 652,817, filed July 12, 1967, now Patent No.

Background of the invention In connection with the drilling of oil andgas wells, it is often necessary to perform various types of operationsin the well bore, some of which may be termed repair operations, as forsealing up leaks or improperly located perforations. The sealing willordinarily be performed by introducing cement into the well casing toform a plug therein adapted to seal up the leaks or improperly locatedperforations. The cement plug must then be drilled out and the casingreperforated at the proper location or other operations performed, asmay be necessary in each particular case.

In conventional operations of the type described, it is necessary that aseries of runs with drill pipe, tubing, wire line strings be made inorder to introduce the successive forms of tools required to perform theseveral operations which may be involved. Each time a string of pipecarrying well tools is run into and out of a well, a considerable amountof time is involved which can be very expensive, particularly for theoperations conducted at great depths, as is often the case. Also, theAremoval and re-introduction of pipe strings into a well may cause lossof control so as to result in hazards to the well, such as blow-out, andthe like.

For example, in a not uncommon situation where a well casing has beenperforated at a location which does not communicate with the producingformation or a desired section thereof, it is necessary to shut-offthese perforations and reperforate at the correct locations. Closing-olfof the undesired perforations is generally done by packingoi the wellbore at the proper points and placing a body of cement in the well boreat a location such as to plug the incorrectly located perforations. Veryoften this is done under pressure to squeeze oif the perforations. Thisoperation requires the running of a string of pipe and 3,454,090Patented July 8, 1969 t" .a ICC other equipment, as may be required, forproperly placing the cement, and this equipment must then be removedfrom the well bore. Thereafter, as soon as the cement has hardened adrilling string carrying a drill bit must be run back into the well todrill out the cement plug to clear the bore hole. This string must thenbe withdrawn from the well and preplaced by a pipe or Wire line stringcarrying a perforating gun to reperforate the casing at the properlocation. Thereafter, a string of tubing or the like, must be run andset as a production string for the well.

Thus, it will be seen that several trips, requiring running andwithdrawing pipe strings and tools, must be made into and out of thewell bore to complete the series of operations outlined above, all ofwhich necessarily require a substantial amount of time which, inconventional deep well drilling operations, is very costly; or, as notedpreviously, may prove hazardous to the successful completion of theWell.

Summa-ry of the invention The present invention is directed to a toolstring for use in a well bore by which a plurality of operations, suchas those described above, may be performed in a well bore, using asingle pipe string, herein sometimes termed a primary pipe string, forperforming the several operations required without having to withdrawthe same from the Well bore.

In accordance with the present invention, the tool string comprises thecombination of a pipe string designed to function as a drill string,carrying on its lower end a twopart bit comprising, a main bit having anaxial bore aligned with the bore of the pipe string, and a tubular pilotbit removably secured in the bore of the main bit to function as part ofthe main bit, and upon removal from the main bit, to clear the bore ofthe pipe string and main bit for passage of other tools employed forconducting some of the other operations required.

The general assemblage of apparatus described above has been disclosedin the aforementioned copending application, Ser. No. 639,451. Thepresent invention adds additional structural elements thereto forperformance of still other operations required in connection with theprocedures employed in well repair operations, such as those describedabove.

The apparatus in accordance with the present invention, includes inaddition to the drill pipe string and two-part bit, a packer mounted onthe pipe string and arranged to be set and released by manipulation ofthe pipe string for use in sealing 0E above the formations to be pluggedand reperforated, and for use in squeezing cement or other uids into thesurrounding formations. The packer also is provided with novel means bywhich it may be employed as a scraping tool adapted to scrape the wallof the surrounding casing by reciprocation of the tool string, in orderto effectively clean the surface of the casing into which cement is tobe introduced, to thereby assure an effective bond between the cementand the casing.

By use of the apparatus in accordance with this invention, variousoperations may be conducted either before or after perforation, forexample. More particularly, the well bore below the bit may be closedoif with a cement plug by employing the tool string, iirst, as a wallscraping device, and thereafter as a cementing string for placing thecement while the complete two-part bit is in place on the lower end ofthe drill string; and, after the cement has hardened, the drill string,including the bit, may be employed to drill out the cement plug prior tothe running of a perforating gun, or some other tool to be employed forperforming some other operation in the well bore. Thereafter, the drillpipe string, with the pilot bit portion removed, may be employed as theproduction string for the well, the packer carried thereon having beenset to seal oi the well bore between the pipe string and the surroundingcasing above the producing section. The packer may also be used in thecourse of the cementing operation where a squeeze procedure is found tobe desirable.

This invention includes the apparatus described which may be employed toperform a plurality of operations in the well bore with a single primarypipe string, without withdrawing the same from the Well bore during thecourse of such operations.

Other and more specific objects and advantages of this invention willbecome more readily apparent from the following detailed descriptionwhen read in conjunction with the accompanying drawing which illustratesthe invention.

In the drawing:

FIGS. 1A, 1B, and 1C, together, constitute a longitudinal,cross-sectional view of a tool string comprising the apparatus inaccordance with this invention, the apparatus being shown inside a wellcasing with a packer in unset condition in the casing;

FIGS. 2 and 3 are generally diagrammatic views showing the apparatus atdiierent stages in the operation of plugging with cement a section of awell casing containing undesired perforations opposite an earthfor-mation;

FIGS. 4 to 7, inclusive, are diagrammatic illustrations similar to FIGS.2 and 3, showing various additional steps in the operations of the toolstring; and

FIGS, 8 and 9 are cross-sectional views taken generally along lines 8-8and 9--9, respective, of FIG. 1B.

Referring now to the drawings, the tool string comprises:

(a) A pipe string S, which is preferably a string of conventional drillpipe;

(b) A packer, designated generally by the letter P, having a centraltubular support or mandrel M which is connected into the drill string toform a portion thereof, as by means of the collar Q;

(c) A tubular extension E threadedly connected to the lower end ofmandrel M to form an additional part of the drill pipe string; and

(d) A two-part drill bit, designated generally by the letter B,threadedly connected to the lower end of extension E.

The latter may carry a centralizer S.

Packer P may be of any suitable and generally conventional form. In theexemplary form illustrated, it is substantially identical with thatdisclosed particularly in FIGS. 9A and 9B of the aforementionedcopending application, Ser. No. 615,023, comprising the severalassemblies designated therein by the letters H', P', A and R However,the anchor assembly A of the present packer embodies certainimprovements over anchor assembly A of the packer illustrated anddescribed in the aforementioned application and will be described ingreater detail hereinafter. It should be noted, however, that except forthe modied anchor assembly, the details of the packer herein illustrateddo not form a part of the present invention, and that anchor assembly Ais adapted for use with other forms of packer or other well tools, aswill appear subsequently.

Bit B is of the two-part, pump out form disclosed in the aforementionedapplication, Ser. No. 620,807, but may also be of the latched formillustrated in aforementioned application Ser. No. 639,451.

In the form illustrated, bit B comprises a main bit B and a pilot bit B.Main bit B includes a tubular body 10 having an axial bore 11 andcarrying radially extending cutter blades 12 terminating at their lowerends in cutter teeth 12a. Pilot bit B includes a tubular shank 13coaxially disposed in bore 11 and releasably secured therein to the mainbit by means of shear pins 13a. Shank 13 carries on its lower end aplurality of angularly spaced cutters 14, the upper ends of which areseated in slots 14a to lock the pilot bit against rotation relative tothe main bit. The spaces between cutters 14 form fluid passagescommunicating through the bore of shank 13 and via the bores of theintervening members with the bore of pipe string S. The inner end ofshank 13 defines a seat 30 for engagement of a suitable plugging device,such as the ball K (FIG. 5), which may be pumped through the bore ofpipe string S for purposes to be described hereinafter. Seal packing 31is disposed about shank 13 for sealing between the latter and the wallof bore 11 of the ymain bit.

Packer P includes the tubular body 15 slidably mounted about mandrel M,and the annular resilient seal element 16, the upper end of which issecured to body 15 by the abutment ring 17. The lower end of sealelement 16 carries the expander sleeve 18, the lower end of which isformed to provide the downwardly and inwardly tapering expander cone 19.

Anchor assembly A is mounted on mandrel M below eexpander cone 19 andcomprises a tubular slip cage 20 arranged for slidable movement on themandrel and has mounted on its upper end a plurality of upstanding,angularly spaced, pipe-gripping wedges or slips 21 arranged for radialmovement outwardly upon engagement by expander co'ne 19 in response todownward movement of mandrel M and body 15 relative to cage 20.

Slip cage 20 carries a plurality of angularly spaced, generallyrectangular wiper blocks 22 biased outwardly by spring means 23 tofrictionally engage the wall of a surrounding well casing C in which thetool string is run. Each of the wiper blocks carries on its outer face aseries of vertically spaced, outwardly projecting arcuate teeth 24, theedges of which are disposed to effectively scrape the inner wall surfaceof the surrounding casing when the tool string is reciprocated in thecasing.

As best seen in FIGS, 1B, 8 and 9, the wiper blocks are arranged in atleast two sets in axially spaced relation on the slip Cage, the blocksof one set being angularly oriented with respect to the other so thatthe edges of the teeth 24 of the several blocks will effectively coverthe entire circumferences of the inner wall of casing C to therebyassure effective cleaning of scale or other detritus from the casingwall in response to the reciprocation of the tool string, as will appearsubsequently.

A latch means, designated generally by the letter L, is arranged betweenpacker body 15 and mandrel M t0 initially hold the packer in unsetposition, and is arranged to be released by means of a releasing sleeve25 slidably disposed about mandrel M below anchor assembly A. Release oflatch L by means of sleeve 25 is effected by longitudinal reciprocationtransmitted to mandrel M through pipe string S, as fully described inthe aforementioned application, Ser. No. 615,023.

Operation of the tool string will now be described with referenceparticularly to FIGS. 2 to 7, inclusive.

The tool string, assembled as shown in FIGS. 1A, 1B, and 1C, and withpacker P and anchor assembly A in the retracted or unset condition, asshown, will be inserted into casing C through the bore of a conventionalpreventor stack R mounted on the upper end of casing C. Casing C willextend through earth formations F.

As illustrated in FIG. 2, casing C will previously have been perforatedby the perforations G at an unsuitable location which it is desired toclose off so that the earth formation may be reperforated at a lower andpreferred location.

When the packer has attained a position in the casing substantiallyopposite formation F, the entire tool string will be operated to performa series of short reciprocatory movements within a section of the casingto cover a length thereof extending well above and below perforations G,so that scraping teeth 24 may be caused to effectively scrape andthoroughly clean the inner surface of this section of casing C. It willAbe understood that the stroke of these reciprocatory movements will beless than that required to bring releasing sleeve 25 intolatch-releasing position.

When this operation have been completed, liquid cement D will beintroduced through pipe string S and deposited in the section of casingC opposite formation F, as seen in FIG. 2. Conventional cementingprocedures will be used, employing displacing uids, and the cement willbe discharged through the passages in bit B.

The next stage of operation will usually be the removal of excess cementby reverse circulation of washing fluid through openings in thepreventor stack to wash the portion of the cement which extends abovethe desired level in the casing back through the bit passages and boreof pipe string S to the surface.

As soon as washing out of the excess cement has been completed, if itshould be found desirable to squeeze the cement through openings G intothe existing formations, packer P will be set by appropriatelongitudinal movements of the operating pipe string, as described in theaforementioned application, Ser. No. ,615,023. With the packer set,fluid pressure may be applied to the body 0f cement in place oppositeformation F suilicient to force the cement through openings G into therelated portions of the earth formation.

When the cement has set, packer P will be released, also as described inaforementioned application, Ser. NO- 615,023. Pipe string S will now befree to rotate, and will now be operated as a drilling string, causingbit B to drill out the cement plug which has been formed in casing Copposite formation F, as illustrated in FIG. 4, and thereby clear thebore of casing C.

The next step, illustrated in FIG. 5, is to drop ball K through the boreof pipe string S until it engages seat 30' and closes the bore of shank13 of the pilot bit. Then fluid pressure will be applied through pipestring S t0 break shear pin 13a and expel pilot bit B from bore 11 ofthe main Ibit, to thereby clear the bore of the entire tool string forthe passage of other tools, as may be required for the next stage in theoperation of the tool string.

In the illustrative embodiment, the next steps, illustrated in FIGS. 6and 7, will involve reperforating formation F at a lower level andemploying the tool string as a production string. In performing thesesteps, preventor stack R will be replaced by a casing hanger T in whichthe upper end of pipe string S will be suitably hung by conventionalmeans and the casing hanger will be surmounted by a conventionalChristmas tree X including a lubricator E to enable introduction andremoval of tools while the well is under pressure.

Packer P will again be set to seal olf the space between pipe string Sand casing C above formation F. Then a conventional perforating gun Isuspended on cable N will be run through lubricator E and pipe string Sto a point at which new perforations are to be made in formation F. Thegun will then -be fired in the known manner, producing the newperforations G', whereupon the gun will be withdrawn from the well, andthe latter brought into production through pipe string S which will nowfunction as the production string.

From the foregoing, it will be evident that the apparatus describedenables the performance of a plurality of operations in a well throughthe medium of a single operating string without requiring the removal ofthat string from the well bore at any stage of operation.

It will be understood that various changes may be made in the details ofthe apparatus described, within the scope of the appended claims butwithout departing from the spirit of this invention.

I claim:

1. In an anchor assembly for use with well tools, a subcombinationcomprising:

a tubular support adapted to form a part of a tool string,

a cage member slidably mounted about the support,

a plurality of angularly spaced wiper blocks mounted in said cage forfrictionally engaging the Wall of a surrounding Well pipe, and

scraper elements carried by said wiper blocks disposed to scrape theentire circumference of said wall in response to reciprocation of saidsupport.

2. In an anchor assembly according to claim 1, a plurality ofpipe-gripping slips mounted on said cage for radial movement relative tosaid wall, and an expander means mounted on said support for actuatingsaid slips in response to longitudinal movement of said support relativeto said cage.

3. In an anchor assembly according to claim 1, said wiper blocks beingarranged in at least two axially spaced sets, one of said sets beingangularly olf-set relative to the other.

4. In an anchor assembly according to claim 1, wherein said scraperelements comprise one or more vertically spaced outwardly projectingarcuate teeth having longitudinal edges disposed for scraping engagementwith Said Wall.

5. In a well tool string, the combination comprising:

(a) a tubular support adapted to form a part of a tOOl string;

(b) a seal packer mounted on the support;

(c) a cage member slidably mounted about the support for axial movementrelative to said packer to set and release the latter;

(d) a plurality of angularly spaced wiper blocks mounted in said cagefor frctionally engaging the wall of a surrounding well pipe; and

(e) scraper elements carried by said wiper blocks disposed to scrape theentire circumference of said wall in response to reciprocation of saidsupport.

6. In a well tool string according to claim 5,

(a) a plurality of pipe-gripping slips mounted on said cage for radialmovement relative to said support; and

(b) an expander means carried by said packer means for actuating saidslips in response to longitudinal movement of said support relative tosaid cage.

References Cited UNITED STATES PATENTS 2,590,502 3/1952 Brown 166-1382,836,251 5/1958 Claypool et al. 166-173 3,031,016 4/1962 Conrad 166-1733,128,826 4/1964 Brown 166-216 X DAVID H. BROWN, Primary Examiner.

U.S. Cl. X.R. l66-2l6

